Possible Duplicate:
How is the default user avatar generated?

Stack overflow uses a default generated image called Identicons for users. They look like this:

one one one one

A basic overview of the system is here.

My question is, what is the algorithm that Gravatar uses to generate these? The question here provides a link to the original 9-panel version of identicons. Gravatar's version uses a 16-panel version.

Is the source available?

  • 1
    I think this actually makes more sense on SO than on Meta, but there's no option to migrate in that direction. EDIT: Turns out it's been asked there before Aug 14, 2010 at 3:49

1 Answer 1


I've found the PHP implementation for the 16-panel identicons.


This has the PHP source for version 1.02.

  • Good find! Since we already have an FAQ entry about Identicons, I've added this link to the answer there.
    – Pops
    Sep 26, 2012 at 14:55

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